Hi cwhsu;
28800 is the default value for wait_timeout, so either your option file is not being used, or that particular setting is getting overwritten by another option file. I’d first check the ownership and permissions on your “mysqld.cnf” option file. Normally the permissions should be something like “640” (chmod 640), and owned by whatever user you run your DB as (i.e. chown mysql:mysql). If that is not the issue, then I’d start looking at the other option files that can be used by default to see if the setting is getting overwritten somewhere else (especially /etc/my.cnf).